Electric water pump

ABSTRACT

The present invention provides an electric water pump, in which the direction and angle of a volute casing, through which coolant is suctioned and discharged, with respect to an electric motor fixedly mounted in a vehicle body can be freely adjusted during assembly according to vehicle model. The electric water pump of the present invention may preferably include an electric motor for rotating an impeller; a volute cover including an inlet and an outlet and forming a front portion of a spiral chamber; an interface including a mechanical seal, interposed between the electric motor and the interface, and interposed between the electric motor and the volute cover to form a rear portion of the spiral chamber, and a rotatable connection member to allow the interface to be rotated at a desired angle with respect to the electric motor and connected by a bolt such that the direction and angle of the inlet and the outlet of the volute cover are adjusted.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims under 35 U.S.C. §119(a) the benefit of Korean Patent Application No. 10-2009-0115433 filed Nov. 26, 2009, the entire contents of which are incorporated herein by reference.

BACKGROUND

(a) Technical Field

The present disclosure relates, generally, to a water pump. More particularly, it relates to an electric water pump, which can be mounted in a vehicle by freely adjusting the coolant discharge direction and angle.

(b) Background Art

In the case of a typical internal combustion engine vehicle, an engine driven water pump driven by the power of the engine transmitted through a pulley and a belt is widely used as a water pump for circulating coolant in the vehicle.

Recently, an electric water pump driven by electricity is preferably used instead of the engine driven water pump. In the electric water pump, when an electric motor is preferably driven by electricity supplied from a battery, etc., an impeller is suitably rotated to suction and discharge coolant.

It is known that the electric water pump improves fuel efficiency by 2 to 3% since it does not require the driving power of the engine. Moreover, since the electric water pump can precisely control the temperature of the coolant, a number of automobile manufacturers apply electric water pumps to mass-produced vehicles.

When there is a situation where the operation of the engine is stopped in an EV mode, for example, in an electric vehicle such as a hybrid vehicle, since the engine for driving the water pump is not mounted in a fuel cell vehicle or a pure electric vehicle, it is necessary to use the electric water pump as the water pump for circulating the coolant in these vehicles.

FIG. 1 is a schematic diagram showing the configuration of a cooling system in which an electric water pump is suitably employed. As shown in the figure, the cooling system for a fuel cell vehicle, a hybrid vehicle, or an internal combustion engine vehicle (e.g., typical gasoline engine vehicle) includes an engine (stack) cooling system and an electronic component cooling system.

Preferably, the cooling system for the engine or the fuel cell stack circulates coolant through the engine or the fuel cell stack using an electric water pump to suitably dissipate the heat of combustion of the engine or the reaction heat of the fuel cell stack and comprises an electric water pump for circulating coolant, a reservoir for storing the coolant, a radiator for dissipating heat from the coolant to the outside, a three-way valve for switching the circulation path of the coolant, etc.

It is necessary to control the temperature of the coolant in order to suitably dissipate the heat generated by the engine or the fuel cell stack through the coolant as a heat transfer medium and to satisfy the operation conditions and efficiency of the engine or the fuel cell stack with the above-configuration.

Preferably, in the electronic component cooling system, a small electric pump and a radiator are suitably employed to cool a drive motor for driving the vehicle, an air blower controller, a high voltage DC converter, a low voltage DC converter, a drive motor controller, a high voltage junction box, etc. by water-cooling and to suitably transfer and dissipate heat generated thereby.

A volute pump, which is a kind of centrifugal pump, is widely used as the electric water pump for a vehicle. The volute pump includes an impeller rotated by an electric motor such that when the impeller is suitably rotated by the electric motor, the coolant flowing through an inlet in the center of a volute casing passes through a spiral chamber provided in the volute casing and is suitably discharged through an outlet by centrifugal force generated at this time.

FIG. 2 is a perspective view showing a conventional electric water pump. As shown in the figure, the electric water pump 1 preferably comprises an electric motor 10 as a drive source and a hydraulic portion 20 for generating coolant suction and discharge forces. The hydraulic portion 20 includes a volute casing 21 in which a spiral flow space, i.e., a spiral chamber is formed, and an impeller (not shown) rotated by the electric motor 10.

The conventional electric water motor 1 has a structure in which an interface, i.e., a mechanical seal (not shown), for sealing a water flow space and a motor chamber and separating them from each other is integrally mounted in a motor housing 11 and the volute casing 21 including an inlet 22 and an outlet 23 is covered on the motor housing 11.

Preferably, a mounting portion 12 is suitably provided on the motor housing 11 to mount the electric water pump 1 in the vehicle. Here, the motor housing 11, the mechanical seal integrally mounted in the motor housing 11, and the volute casing 21 integrated with the motor housing 11 by means of the mechanical seal are integrally fixed and mounted.

Since the volute casing 21 is suitably integrated with the electric motor 10 by means of the mechanical seal mounted in the motor housing 11, the coolant discharge direction and angle of the volute casing 21 with respect to the motor housing 11 fixed to the vehicle body are suitably fixed.

Accordingly, the conventional water pump 1 has the structure in which the volute casing 21 including the inlet 22 and the outlet 23 is covered on the motor housing 11 in which the mechanical seal is suitably integrated, the position, direction, and angle of the inlet 22 and the outlet 23 with respect to the electric motor 10 mounted in the vehicle are fixed during the design phase.

Since the volute casing cannot be rotated with respect to the motor housing and the mounting portion mounted in the vehicle, or since the direction of the volute casing cannot be changed, it is very difficult to flexibly change the direction of the volute casing integrated with the motor housing or to rotate only the volute casing during assembly when the mounting position and direction of the motor housing mounted in the vehicle are determined by the mounting portion at a predetermined position in a specific vehicle model (i.e., the direction of the coolant outlet is fixed).

As a result, when it is necessary to change the coolant discharge direction according to the vehicle model, the type of the engine, the packaging of the vehicle, etc., a water pump having a different structure is suitably required for each vehicle model, and it is necessary to change the design of the pump to suitably reset the discharge direction every time when a new vehicle model is developed and mass produced.

Accordingly, there remains a need in the art for electric water pumps that can be freely adjusted during assembly so as to be commonly used in a variety of vehicle models.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

SUMMARY OF THE DISCLOSURE

The present invention, in preferred aspects, provides an electric water pump, in which the coolant discharge direction and angle of a volute casing with respect to an electric motor fixedly mounted in a vehicle body can be freely adjusted during assembly so as to be commonly used in a variety of vehicle models.

In a preferred embodiment, the present invention provides an electric water pump including an electric motor for rotating an impeller; a volute cover including an inlet and an outlet and suitably forming a front portion of a spiral chamber; an interface preferably including a mechanical seal, suitably interposed between the electric motor and the interface, and suitably interposed between the electric motor and the volute cover to form a rear portion of the spiral chamber, and a rotatable connection member to allow the interface to be rotated at a desired angle with respect to the electric motor and connected by a bolt such that the direction and angle of the inlet and the outlet of the volute cover are adjusted.

In a preferred embodiment, the rotatable connection member may preferably include a plurality of screw holes for bolt fastening or a plurality of through holes for bolt insertion formed at regular intervals in the circumferential direction on an edge portion of the interface to which a motor housing connection portion of the electric motor is suitably connected.

In another preferred embodiment, the rotatable connection member may preferably include a plurality of screw holes for bolt fastening or a plurality of through holes for bolt insertion formed at regular intervals in the circumferential direction on a motor housing edge portion of the electric motor to which a connection portion of the interface is connected.

In still another preferred embodiment, the rotatable connection member may preferably include a plurality of bolts fixedly provided at regular intervals in the circumferential direction on the edge portion of the interface to which the motor housing connection portion of the electric motor is connected, the plurality of bolts being suitably fastened to the motor housing connection portion.

In yet another preferred embodiment, the rotatable connection member may include a plurality of bolts fixedly provided at regular intervals in the circumferential direction on the motor housing edge portion of the electric motor, to which the connection portion of the interface is connected, the plurality of bolts being fastened to the connection portion of the interface.

Other aspects and preferred embodiments of the invention are discussed infra.

It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g. fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles.

The above features and advantages of the present invention will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated in and form a part of this specification, and the following Detailed Description, which together serve to explain by way of example the principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present invention will now be described in detail with reference to certain exemplary embodiments thereof illustrated the accompanying drawings which are given hereinbelow by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 is a schematic diagram showing the configuration of a cooling system in which an electric water pump is employed;

FIG. 2 is a perspective view showing a conventional electric water pump;

FIG. 3 is a front perspective view of an electric water pump in accordance with an exemplary embodiment of the present invention;

FIG. 4 is a rear perspective view of an electric water pump in accordance with an exemplary embodiment of the present invention;

FIG. 5 is a front perspective view of an electric water pump in accordance with an exemplary embodiment of the present invention, from which a volute cover is removed;

FIG. 6 is a rear view of an assembly of a volute cover and an interface in an electric water pump in accordance with an exemplary embodiment of the present invention; and

FIG. 7 is a front perspective view of an electric water pump in accordance with an exemplary embodiment of the present invention, from which a motor housing is removed.

Reference numerals set forth in the Drawings includes reference to the following elements as further discussed below:

100: electric water pump 110: electric motor 111: motor body 112: motor housing 113: mounting bracket 114: connection portion 120: interface 121: spiral flow path 122: rear edge portion 123: screw hole 124: connection portion 130: volute cover 131: inlet 132: outlet 133: spiral flow path 134: connection portion

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION

In one aspect, the present invention features an electric water pump comprising an electric motor for rotating an impeller, a volute cover, an interface comprising a mechanical seal, and a rotatable connection member to allow the interface to be rotated at a desired angle with respect to the electric motor.

In one embodiment, the volute cover further comprises an inlet and an outlet, and wherein the volute cover forms a front portion of a spiral chamber.

In another embodiment, the interface is interposed between the electric motor and the interface, and interposed between the electric motor and the volute cover to form a rear portion of the spiral chamber.

In another further embodiment, the rotatable connection member is connected by a bolt such that the direction and angle of the inlet and the outlet of the volute cover are adjusted.

Hereinafter reference will now be made in detail to various embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. While the invention will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention to those exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

According to preferred embodiments as described herein, the present invention provides an electric water pump, in which the direction and angle of a volute casing, through which coolant is suitably suctioned and discharged, with respect to an electric motor fixedly mounted in a vehicle body can be freely adjusted according to a vehicle model during assembly.

Typically, the mass production cost of electric water pumps is higher than that of engine driven water pumps. In order to reduce the cost gap, a standard structure is adopted, which can be commonly used in a variety of vehicle models, rather than to design and manufacture various pumps, in which the coolant discharge direction is fixed, according to the vehicle model, the type of the engine, the packaging of the vehicle, etc.

For this purpose, the present invention provides a standard structure in which a volute casing (including a volute cover and an interface which form a spiral chamber) can be suitably rotated at a desired angle such that the electric water pump can be suitably mounted in a vehicle by freely adjusting the coolant suction and discharge directions without changing the structure and design of the pump according to the vehicle model.

FIG. 3 is a front perspective view of an electric water pump in accordance with a preferred exemplary embodiment of the present invention, FIG. 4 is a rear perspective view of an electric water pump in accordance with another preferred exemplary embodiment of the present invention, and FIG. 5 is a front perspective view of an electric water pump in accordance with another further preferred exemplary embodiment of the present invention, from which a volute cover is removed.

FIG. 6 is a rear view of an assembly of a volute cover and an interface in an electric water pump in accordance with a preferred exemplary embodiment of the present invention, which shows an example in which a plurality of screw holes 123 (each having a thread on the inner circumference) are suitably formed at regular intervals along a rear edge portion 122 of an interface 120, and a spiral flow path 121 for forming a spiral chamber is provided in the interface 120.

FIG. 7 is a front perspective view of an electric water pump in accordance with an exemplary embodiment of the present invention, from which a motor housing is preferably removed, which shows an example in which a plurality of screw holes 123 are formed at regular intervals along the rear edge portion 122 of the interface 120 assembled with a motor body 111.

As shown in the figures, the electric water pump 100 of the present invention is a volute pump, a kind of centrifugal pump, and includes a hydraulic portion having a spiral chamber and an impeller (not shown) to generate coolant suction and discharge forces and an electric motor 110 as a drive source for rotating the impeller.

In detail, the electric water pump 100 of the present invention preferably comprises the electric motor 110 driven by electric power supplied from the outside, the interface 120 including a mechanical seal (not shown) suitably interposed between the electric motor 110 and the interface 120 and forming a rear portion of the spiral chamber as a water flow space, and a volute cover 130 preferably including an inlet 131 and an outlet 132 and forming a front portion of the spiral chamber.

According to certain preferred embodiment, the electric motor 110 includes the motor body 111 generating a suitable rotational force for rotating the impeller and a motor housing 112 for surrounding the motor body 111, the motor body 111 and the motor housing 112 being integrally assembled.

Preferably, the motor body 111 has a typical structure including a stator and a rotor (including a rotor shaft), and the motor housing 112 preferably includes a mounting portion such as a mounting bracket 113 for suitably mounting the electric motor 110 to a vehicle body.

According to preferred embodiments of the present invention, a motor chamber, which is an inner space where the stator and the rotor are provided, of the motor body 111 is suitably sealed by the mechanical seal provided in the rear portion of the interface 120 and spatially separated from the spiral chamber, formed by the interface 120 and the volute cover 130, by the mechanical seal.

Preferably, the rotor shaft of the motor body 111 is suitably connected to the impeller located in the spiral chamber in a state where the sealing is suitably maintained by the mechanical seal, and thereby the impeller can be suitably rotated by the rotation of the rotor shaft.

According to preferred embodiments of the present invention, a rear portion of the interface 120 is suitably connected to a front portion of the motor body 111 such that the mechanical seal provided in the rear portion seals the motor chamber of the motor body 111 separately from the motor housing 112, which has a distinct difference from the conventional structure in which the mechanical seal is integrally mounted in the motor housing 112.

Accordingly, the interface 120 including the mechanical seal provided in the rear portion thereof is suitably separated from the motor housing 112, the mechanical seal is not integrally mounted in the motor housing 112 in a conventional manner but preferably included in the separated interface 120, and the interface 120 is suitably interposed between the electric motor 110 and the volute cover 130 and separately assembled, which are quite different from the conventional structure.

According to further preferred embodiments, the electric water pump 100 of the present invention has a structure in which a spiral flow path 121 is suitably formed on the inner surface of the interface 120 such that the inner space of the interface 120 forms the rear portion of the spiral chamber, and a spiral flow path 133 is formed on the inner surface of the volute cover 130 such that the inner space of the volute cover 130 forms the rear portion of the spiral chamber.

Accordingly, the spiral chamber is suitably formed when the volute cover 130 and the interface 120 are assembled together, and the assembly of the two components preferably serves as a volute casing which generates a centrifugal force to discharge the coolant.

Preferably, the rear edge portion 122 of the interface 120 is suitably connected to a front connection portion 114 of the motor housing 112 surrounding the motor body 111 by bolts such that the interface 120 and the electric motor 110 are integrally assembled.

Accordingly, the spiral chamber formed by the assembly of the volute cover 130 and the interface 120 serves as the conventional volute casing in which the suctioned water rotates in the spiral chamber to suitably generate the centrifugal force.

Preferably, the inlet 131 is provided in the center of the volute cover 130 and the outlet 132, through which the water is suitably discharged in a direction tangential to the direction of the water flow (i.e., the rotation direction of water) in the spiral chamber, is provided. Further, a connection portion 134 of the volute cover 130 and a connection portion 124 of the interface 120 are suitably connected together by bolts, and thereby the volute cover 130 and the interface 120 are integrally assembled.

Accordingly, as a result, the coolant flowing through the inlet 131 in the center of the volute cover 130 passes through the spiral chamber that is suitably provided in the volute cover 130 and the interface 120 and is suitably discharged through the outlet 132 by the centrifugal force generated at this time.

Further, as mentioned above, the assembly of the volute cover 130 and the interface 120 serves as the volute casing having the spiral chamber. Here, in order to easily adjust the direction in which the water is discharged, i.e., the direction of the outlet 132 with respect to the electric motor 110 fixed to the vehicle body, the interface 120 connected to the motor housing 112 of the electric motor 110 preferably includes a rotatable connection member to allow the interface 120 to be rotated at a desired angle with respect to the motor housing 112.

Preferably, the rotatable connection member, for example as shown in FIGS. 6 and 7, may comprise a plurality of screw holes 123, each having a thread on the inner circumference, formed at regular intervals in the circumferential direction on the rear edge portion 122 of the interface 120 to which the connection portion 114 of the motor housing 112 is suitably connected.

Preferably, when the screw holes 123 are formed at regular intervals along the rear edge portion 122 of the interface 120, it is possible to appropriately rotate the interface 120 in the motor housing 112, and thereby it is possible to set the direction of the inlet 131 and the outlet 132 of the volute cover 130 suitably assembled with the interface 120 to any desired direction.

Accordingly, in preferred embodiments of the present invention, it is possible to suitably connect the interface 120 to the motor housing 112 at a desired rotation angle and to suitably connect the connection portion 114 of the motor housing 112 to one of the plurality of screw holes 123 formed at regular intervals. Therefore, it is possible to freely adjust the direction and angle of the inlet 131 and the outlet 132 of the volute cover 130 according to the vehicle model, the type of the engine, the packaging of the vehicle, etc. (however, the direction and angle of the inlet are not changed when it is located in the middle of the volute cover as shown in the figures).

For example, according to preferred exemplary embodiments, for example, in the case where twenty four screw holes 123 are formed at an angle of 15° along the rear edge portion 122 of the interface 120, it is possible to suitably assemble the outlet 132 at a total of twenty four angles.

Preferably, during assembly, as shown in FIG. 6, the interface 120 and the volute cover 130 are suitably assembled and then the interface 120 is assembled with the motor housing 112 by adjusting the angle of the outlet 132 of the volute cover 30 to a desired angle. Subsequently, a bolt is suitably inserted into a connection hole 114 a, formed in each connection portion 114 of the motor housing 112, and then connected to one of the screw holes 123 of the interface 120.

Accordingly, since the water pump 100 is suitably mounted in the vehicle in such a manner that the interface 120 is appropriately rotated to adjust the angle of the outlet 132 to a desired angle, it is possible to commonly use the water pump 100 in a variety of vehicle models.

According to other further preferred embodiments, although the rotatable connection member is suitably formed in the interface 120 in the exemplary embodiment as shown in the figures, the same rotatable connection member may be suitably formed on a front edge portion of the motor housing 112.

Preferably, in certain exemplary embodiments, a plurality of connection portions are suitably formed to protrude from the rear surface of the interface 120, and instead, a plurality of screw holes each having a thread on the inner circumference are suitably formed at regular intervals in the circumferential direction on the front edge portion of the motor housing 112 to which the connection portions are connected.

Accordingly, the rotatable connection member may be suitably formed with the screw holes on the front edge portion of the motor housing 112. Preferably, the angle of the outlet 132 of the volute cover 130 is suitably adjusted to a desired angle, and then the interface 120 is assembled with the motor housing 112 in such a manner that a bolt is inserted into a connection hole, formed in each connection portion of interface 120, and then connected to one of the screw holes of the motor housing 112.

In another exemplary embodiment of the present invention, although not shown in the figures, a plurality of through holes, through which a bolt is simply inserted, may be suitably formed at regular intervals on the rear edge portion 122 of the interface 120 or the front edge portion of the motor housing 112, instead of the screw holes each having a thread on the inner circumference.

Preferably, in this case, a bolt is inserted into the connection hole formed in each connection portion of the motor housing 112 or into the connection hole formed in each connection portion of the interface 120 and then a nut is suitably fastened to the bolt to prevent the bolt from being removed from the connection hole and the through hole.

In a further exemplary embodiment, although not shown in the figures, a plurality of bolts may be fixedly provided at regular intervals in the circumferential direction on the rear edge portion 122 of the interface 120 or on the front edge portion of the motor housing 112.

Preferably, when the plurality of bolts are fixedly provided at regular intervals in the circumferential direction on the rear edge portion 122 of the interface 120, the angle of the outlet 132 of the volute cover 130 is adjusted to a desired angle, and then the interface 120 is suitably assembled with the motor housing 112 in such a manner that one of the plurality of bolts of the interface 120 is suitably inserted into a connection hole formed in each connection portion of the motor housing 112 and then a nut is fastened to the bolt on the opposite side.

In other further embodiments, when the plurality of bolts are fixedly provided at regular intervals in the circumferential direction on the front edge portion of the motor housing 112, the angle of the outlet 132 of the volute cover 130 is suitably adjusted to a desired angle, and then the interface 120 is suitably assembled with the motor housing 112 in such a manner that one of the plurality of bolts of the motor housing 112 is inserted into a connection hole formed in each connection portion of the interface 120 and then a nut is fastened to the bolt on the opposite side.

As described herein, the present invention provides the following advantages.

Unlike the engine driven mechanical pump mounted in the engine, the electric pump requires a separate packaging space. Accordingly, the electric pump is provided as an independent package regardless of the specification of the engine or fuel cell stack, and thus when the vehicle model is changed, it is necessary to modify the design of the electric pump in accordance with the vehicle model even in the same cooling system.

According to the electric water pump 100 of the present invention, in which the interface 120 (which forms the spiral chamber with the volute cover 130) including the mechanical seal is provided separately from the motor housing 112, the assembly of the volute cover 130 and the interface 120 can be suitably rotated and mounted in the electric motor 110 such that the direction and angle of the inlet 131 and the outlet 132 of the volute cover 130 are adjusted to a desired direction and angle. Accordingly, it is possible to freely adjust the direction and angle of the inlet and the outlet of the pump in accordance with a variety of vehicle models only with the standard structure.

In particular, when the use of the standard structure is employed, it is not necessary to modify the design of the electric pump in accordance with the vehicle model, and further, since it is not necessary to manufacture molds for the production of pumps according to the vehicle models, it is possible to considerably reduce the manufacturing cost.

The invention has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents. 

1. An electric water pump comprising: an electric motor for rotating an impeller; a volute cover comprising an inlet and an outlet and forming a front portion of a spiral chamber; an interface including a mechanical seal, interposed between the electric motor and the interface, and interposed between the electric motor and the volute cover to form a rear portion of the spiral chamber, and a rotatable connection member to allow the interface to be rotated at a desired angle with respect to the electric motor and connected by a bolt such that the direction and angle of the inlet and the outlet of the volute cover are adjusted.
 2. The electric water pump of claim 1, wherein the rotatable connection member comprises a plurality of screw holes for bolt fastening or a plurality of through holes for bolt insertion formed at regular intervals in the circumferential direction on an edge portion of the interface to which a motor housing connection portion of the electric motor is connected.
 3. The electric water pump of claim 1, wherein the rotatable connection member comprises a plurality of screw holes for bolt fastening or a plurality of through holes for bolt insertion formed at regular intervals in the circumferential direction on a motor housing edge portion of the electric motor to which a connection portion of the interface is connected.
 4. The electric water pump of claim 1, wherein the rotatable connection member comprises a plurality of bolts fixedly provided at regular intervals in the circumferential direction on the edge portion of the interface to which the motor housing connection portion of the electric motor is connected, the plurality of bolts being fastened to the motor housing connection portion.
 5. The electric water pump of claim 1, wherein the rotatable connection member comprises a plurality of bolts fixedly provided at regular intervals in the circumferential direction on the motor housing edge portion of the electric motor, to which the connection portion of the interface is connected, the plurality of bolts being fastened to the connection portion of the interface.
 6. An electric water pump comprising: an electric motor for rotating an impeller; a volute cover; an interface comprising a mechanical seal; and a rotatable connection member to allow the interface to be rotated at a desired angle with respect to the electric motor.
 7. The electric water pump of claim 6, wherein the volute cover further comprises an inlet and an outlet, and wherein the volute cover forms a front portion of a spiral chamber.
 8. The electric water pump of claim 6, wherein the interface is interposed between the electric motor and the interface, and interposed between the electric motor and the volute cover to form a rear portion of the spiral chamber.
 9. The electric water pump of claim 6, wherein the rotatable connection member is connected by a bolt such that the direction and angle of the inlet and the outlet of the volute cover are adjusted. 